This study developed a theoretical model to explore the antecedents of interpersonal trust and the impact of interpersonal trust and uncertainty on intra- organisational knowledge sharing in highly information-technology-mediated work environments. The proposed model was tested empirically using survey data collected from five telecommunication companies. The findings reveal that inter- personal trust has a positive effect on knowledge sharing, while uncertainty has a negative effect upon knowledge sharing. The results also show that social inter- action ties and shared knowledge-sharing vision are the antecedent factors of interpersonal trust, and that uncertainty regarding knowledge sharing is increased by seeker absorptive capability concerns, reciprocity concerns and fear of losing knowledge power. Some important implications for theory and practice as well as directions for future study are discussed.